安裝openjdk
wget --no-cookies --no-check-certificate --header "Cookie: oraclelicense=accept-securebackup-cookie" \ https://download.java.net/java/GA/jdk10/10.0.2/19aef61b38124481863b1413dce1855f/13/openjdk-10.0.2_linux-x64_bin.tar.gz
2.解壓到/usr/local下
tar zxf openjdk-10.0.2_linux-x64_bin.tar.gz -C /usr/local 3.將目錄換名（也可以不換）
mv /usr/local/jdk-10.0.2 /usr/local/jdk-10
修改方法三:
通過修改profile文件:
vim /etc/profile
/export PATH //找到設置PATH的行，添加
export PATH=/usr/local/mongodb/bin:$PATH
生效方法：系統重啟
有效期限：永久有效
用戶局限：對所有用戶
vim /etc/profile 在最底部添加jdk的路徑 export PATH=PATH:/usr/local/jdk10/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin 保存，重啟服務器 reboot 查看java版本 java -version openjdk version "10.0.2" 2018-07-17 OpenJDK Runtime Environment (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4) OpenJDK 64-Bit Server VM (build 10.0.2+13-Ubuntu-1ubuntu0.18.04.4, mixed mode)
如果把PATH玩壞了用以下操作
1、在命令行中 輸入export PATH=/usr/bin:/usr/sbin:/bin:/sbin（export還能用）
2、然后將path改正確
下載安裝包gz
root@ubuntu:~# wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.5.4.tar.gz root@ubuntu:~# tar -xvf elasticsearch-6.5.4.tar.gz
解壓完成將在當前目錄中創建一組文件和文件夾，然后我們進入bin目錄。
root@ubuntu:~# cd elasticsearch-6.5.4/bin root@ubuntu:~/elasticsearch-6.5.4/bin# bash elasticsearch OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release. [2019-01-09T10:43:22,092][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [unknown] uncaught exception in thread [main] org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:140) ~[elasticsearch-6.5.4.jar:6.5.4] at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:127) ~[elasticsearch-6.5.4.jar:6.5.4] at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-6.5.4.jar:6.5.4] at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-6.5.4.jar:6.5.4] at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-cli-6.5.4.jar:6.5.4] at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:93) ~[elasticsearch-6.5.4.jar:6.5.4] at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:86) ~[elasticsearch-6.5.4.jar:6.5.4] Caused by: java.lang.RuntimeException: can not run elasticsearch as root at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:103) ~[elasticsearch-6.5.4.jar:6.5.4] at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:170) ~[elasticsearch-6.5.4.jar:6.5.4] at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:333) ~[elasticsearch-6.5.4.jar:6.5.4] at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:136) ~[elasticsearch-6.5.4.jar:6.5.4] ... 6 more
報錯很明顯“can not run elasticsearch as root”，所以切換到普通用戶重新來吧。
文件夾權限不夠，修改權限
解決方法： chown -R 用戶名:用戶名 文件（目錄）名